Heat capacities of six liquid esters as a function of temperature

1987 ◽  
Vol 52 (2) ◽  
pp. 251-257 ◽  
Author(s):  
Milan Zábranský ◽  
Vladimír Hynek ◽  
Jana Finkeová-Haštabová ◽  
František Veselý

Heat capacities along the saturation line have been measured in a recently designed calorimeter from the temperature of 293 K up to the temperature given in parentheses behind the esters measured: methyl formate (298 K), ethyl acetate (340 K), butyl acetate (364 K), methyl propionate (342 K), ethyl propionate (348 K), and propyl propionate (367 K).

2011 ◽  
Vol 396-398 ◽  
pp. 1536-1540
Author(s):  
Yan Hua Li ◽  
Lan Wei Zhang ◽  
Wei Jun Wang ◽  
Li Li Zhang ◽  
Xue Han ◽  
...  

The effect of reconstituted milk inoculation with Streptococcus thermophilus TM11 and Streptococcus thermophilus SP 1.1 on soft cheese volatiles was investigated. The impact flavors of 2,3-butanedione, 2,3-pentanedione, ethyl acetate, methyl butyrate, ethyl butyrate, butyl acetate and butyric acid were only detected in the fermented cheeses. Levels of diketones were higher in the cheeses fermented by mixed cultures than single culture, while levels of esters except ethyl acetate and butyl acetate showed an opposite tendency. There was significant difference in the levels of 2-hexenal and 2-nonenal among the cheeses. Other compounds originated from lipid oxidation, Strecker degradation, biosynthesis and forages were not significantly influenced by milk inoculation with Streptococcus thermophilus.


Author(s):  
M. E. Peshekhontseva ◽  
M. A. Maevskiy ◽  
I. S. Gaganov ◽  
A. V. Frolkova

Objectives. The conditions for the effective application of the sharp distillation technique (without a component distributed between the distillate and bottom flows) for the separation of quaternary zeotropic mixtures containing components with similar volatilities were determined. The area of energy advantage for the flowsheet based on the preliminary fractionation of the mixture, compared with the flowsheet, the first distillation column of which works based on the indirect separation mode, was identified for an ethyl acetate–benzene–toluene–butyl acetate system. Energy savings of up to 20% were achieved. The direct and indirect distillation modes can become competitive when the point of the original composition is located near single K-surfaces or in a region with a different ratio of distribution coefficients. Sharp distillation is not suitable for the separation of a mixture containing a pair of components exhibiting relative unity volatility with medium boiling points.Methods. The mathematical modeling in the Aspen Plus V.10.0 software package was chosen as the research method. The simulation was based on the Wilson local composition equation. The relative errors in the description of the phase equilibrium did not exceed 3%.Results. The structure of the vapor–liquid equilibrium diagram and diagram of surfaces of the unit component distribution coefficients were studied for the ethyl acetate–benzene–toluenebutyl acetate and acetone–toluene–butyl acetate–o-xylene systems. Flowsheets based on the sharp, indirect (both systems), or direct (second system) distillation modes were proposed. The distillation process was simulated, and the parameters of the column work were determined (the quality of the substances meets the State Standard requirements of the Russian Federation for minimal energy consumption).Conclusions. Recommendations regarding the use of sharp distillation for the separation of quaternary mixtures containing components with similar volatilities were devised.


1967 ◽  
Vol 20 (9) ◽  
pp. 1815 ◽  
Author(s):  
BG Cox ◽  
PT McTigue

The relative rates of the concurrent A1 and A2 hydrolyses of t-butyl acetate have been measured as a function of solvent composition in water-dimethyl sulphoxide (DMSO) mixtures. A large difference in solvent effect is observed, which correlates well with observed solvent effects on ethyl acetate (A2) and acetal (Al) hydrolyses in the same solvent system. Activity coefficients have been measured for t-butyl acetate, ethyl acetate, and acetal in various water-DMSO mixtures.


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